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This paper introduces a concept of real-time optimization of hybrid fuel-cell power plants as an alternative distributed generation source that improves the power quality and reliability of the power grid. One of the most important issues of plant operation is the optimal control of the power plant, leading to significant economic and environmental benefits. As a commercialized fuel cell technology,...
In this paper, a simple and effective strategy is proposed for the coordination of protective devices in typical radial distribution networks embedding distributed generation units. The proposed strategy benefits from microprocessor-based reclosers and directional elements for feeder relays, and addresses the issues of blinding of protection, false tripping, recloserfuse and fuse-fuse miscoordination,...
Along with the large-scale implementation of distributed generators, the current distribution networks have changed gradually from passive to active operation. State estimation plays a vital role to facilitate this transition. In this paper, a suitable state estimation method for the active network design is proposed. The method takes advantages of the multi-agent system technology to compute iteratively...
The rapid increase in installed distributed generation (DG) has led to concerns about the impact on the proper operation of the protection system. In particular, the limited fault current capability of inverter interfaced distributed generation (IIDG) could lead to malfunctioning of the distribution network protection system which largely relies on overcurrent based protection techniques. The absence...
This paper proposes a new pricing mechanism and dispatch model for reactive power service from distributed generation (DG) resources, including wind turbines and solar photovoltaic plants, connected to a low voltage distribution system. Novel cost functions of reactive power service are proposed for DG resources as well as alternative VAR suppliers such as STATCOM and capacitor banks, taking into...
This panel paper presents some outlines on the energy management of electric power microgrids with hybrid components. The hybrid nature of the microgrid is attributed to renewable energy sourced generation, energy storage, schedulable loads and information enabling technology such as smart meters. The panel paper and the accompanying presentation aim to describe the electric energy management visà-vis...
This paper presents the result of quantitatively evaluating the energy saving effect by the combination of pHV and SOFC as parameters of the usage pattern of pHV and the demand characteristic of a house. First, we modeled energy system models of the house, and derived the optimal operation of pHV and SOFC by the analysis. Then, we compared the analysis result of various driving patterns, driving distances,...
In this paper, a dynamic power limiter at the point of common coupling (PCC) of a micro-grid is proposed. A 60Hz, step-down transformer is generally used at the PCC to connect the micro-grid to the power system grid. Substitution of the conventional 60Hz transformer by a dynamic power limiter has the following advantages: 1) Bi-directional active-power control capability at the PCC which results in...
Microgrids can be viewed as a group of Distributed Generation (DG) units with the capability of operating connected or isolated from the main grid. Most of the work conducted in the area of microgrids focused on developing new control schemes that can maintain the voltage and frequency within standard limits during grid connected and islanded mode of operation. An issue of equal importance is the...
As the issues on market deregulation and renewable energy utilization are gaining significance, distributed generators are planned and installed in distribution systems to supply consumers directly. The distribution system is, therefore facing new challenges on its dynamic behavior with the addition of new dynamic devices. This paper investigates the small signal stability of renewable energy based...
In urban areas, where land is costly, building integrated wind energy conversion systems can be embedded into the existing infrastructure to meet an increasing load demand. Recently small scale wind turbines (less than 10kw) are installed in great numbers on the roof-top of residential houses, commercial and high rising buildings. This paper presents an overview of the current technologies being implemented...
Reliability of distribution systems is an important issue in power engineering for both utilities and customers. Power distribution reliability is closely related to individual component reliability. In this paper, the reliability as measured by certain count indices, mainly the System Average Interruption Duration Index (SAIDI) and the System Average Interruption Frequency Index (SAIFI), is quantified...
Power Systems (PS), have been affected by substantial penetration of Distributed Generation (DG) and the operation in competitive environments. The future PS will have to deal with large-scale integration of DG and other distributed energy resources (DER), such as storage means, and provide to market agents the means to ensure a flexible and secure operation. Virtual power players (VPP) can aggregate...
This paper presents an infrastructure and laboratory implementation of a hardware test-bed system emulating alternate sources and conventional power plant emulators connected as a complete power system. The distributed generation components were connected to the test-bed to study the issues of connecting alternates and various types of loads during operations. The various sources and loads can be...
The increasing presence of single-phase distributed generators and unbalanced loads in the electric power system may lead to unbalance of the three phase voltages, resulting in increased losses and heating. To decrease this voltage unbalance problem three-phase four-wire inverter-connected distributed generation units may be used. In this paper, the influence of the control strategy of three-phase...
Economic, technology and environmental incentives are changing the features of electricity generation and transmission. Centralized power systems are giving way to local scale distributed generations. At present, there is a need to assess the effects of large numbers of distributed generators and short-term storage in Microgrid. To accommodate the high demand of renewable energy and the environment...
The connection of generating sources in the distribution systems is on the increase worldwide. If on one hand this practice brings well-known benefits for the system, on the other, there are several institutional barriers that make difficult its feasibility. This way, the Brazilian National Electric Energy Agency (ANEEL) has developed the so called “Distribution Procedures”, which is a set of rules...
In this paper, a notional Future Renewable Electric Energy Delivery and Management (FREEDM) system has been developed based on a real distribution feeder. The goal is to develop a digital testbed which can be used to show capabilities of this system, and to help the development of especially the new system components and the control schemes for this system. Two digital testbeds have been developed,...
We propose two optimization-based models for computing the allowable penetration level of multiple distributed generators, taking into account voltage regulation constraints. A single level optimization model is developed for computing the maximum penetration level, while a bi-level optimization model is developed to answer the question as to at least how much power a distribution system can accommodate...
This paper presents real time test results arising from the application of a case based reasoning technique for voltage control of a section of existing UK 11kV network. The test network includes two distributed generation schemes. The objective of the case based reasoning technique is to maintain voltages within statutory limits while also maximizing the DG access to the network. The control algorithm...
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